I’m writing this on a cold wet evening so let’s have some good news. First after a very dry late spring and summer we have finally had decent quantities of rain, and as a result the turbine has been generating well – so much so that we have recently passed 1,500MWh generated. As usual, autumn has caused some problems with leaf fall, but the operations team have been keeping on top of intake screen clearance, so we haven’t lost much generation.
Perhaps the most time-consuming task recently has been an OFGEM audit. We were selected at random for what turned out to be a very exacting examination of our history and paperwork as well as the arrangements on site. While we had a few difficulties with locating documents and information from before we were commissioned 13 years ago and had to sort out a few anomalies we were eventually given a “satisfactory” rating. Thanks to everyone who put time into this.
One thing which did emerge from the audit was that our input-output meter was due to be recalibrated or replaced (more than 10 years old). Recalibration would involve several days away from site for the meter (during which time we would be unable to run), plus 2 visits from electricians, so we went for the easier option of just replacement – successfully done last week.
During the autumn we had some increase in vibration from the bottom bearing; after careful examination and testing (as much as could be done without draining the lower end of the turbine) the conclusion was that the bearing was starting to wear, but there was no evidence of imminent failure. However, this has stimulated discussion about potential improvements to access to the bottom bearing. There’s a section on the website detailing the problems we had last time in getting a good enough seal below the turbine for dry(ish) access…we ended up needing divers to achieve a reasonable seal. Mike Ford has designed some changes to the fittings of the outlet screen and the stop logs (the things we use to seal off the lower end of the turbine from the river). Installing the new fittings will need divers again but once installed we should be able to seal off and access the bottom bearing and lower chamber as and when we need. This is planned for the spring unless any problems arise sooner. Meanwhile Mike is also looking at an improved bearing design which should prolong bearing life.
Finally returning to the theme of dry spring and summer, although this won’t be a record calendar year for generation, we have now exceeded our worst total with half of December still to come and a generally wet forecast, so things could be a lot worse!
Rory Newman, Chair of Esk Energy
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